Aprendiz de todo, maestro de nada. "Jack of all trades, master of none"

We all know someone who, without knowing much about anything, gives the impression that they are an expert on everything: someone who, for example, without knowing much about football says with all certainty what the best formation for the team to win the World Cup is, or they claim to be a master of the scientific world after watching two documentaries. This proverb is a warning about this type of person.

In the past, when there were still apprenticeships, the phrase also referred to those who were not ambitious enough, or did not work hard enough to move up the ladder of the working world.

So what do the ignorant know-it-all and the scornful slacker have in common? Neither have any concerns about learning more or progressing. They stay where they are.